We've all watched horror films where the characters seem to have lost their senses.
On a stormy night, when they are stranded in a large, secluded, country estate and the electricity has gone and the bodies of a few members of their group have been found, they light some candles . . . and decide to split up into small search parties.
Or, there is a mad killer in the area. A couple finds evidence that he has been living at the old, abandoned cabin, but wait, the cabin has a dark basement! They can barely see down those stairs! So where do they go?
A good exercise: See if you can describe some assumptions and activities your team has embraced that might cause an outsider to shout, "Don't go into that room!"